diff --git a/Documentation/device-mapper/cache.txt b/Documentation/device-mapper/cache.txt
index ff0841711fd524063e2acf0fa4644ec2fbb4b764..8ae1cf8e94daeb6cf142e24624d0e5f4d99d728b 100644
--- a/Documentation/device-mapper/cache.txt
+++ b/Documentation/device-mapper/cache.txt
@@ -206,6 +206,9 @@ Optional feature arguments are:
                   in a separate btree, which improves speed of shutting
 		  down the cache.
 
+   no_discard_passdown	: disable passing down discards from the cache
+			  to the origin's data device.
+
 A policy called 'default' is always registered.  This is an alias for
 the policy we currently think is giving best all round performance.
 
diff --git a/Documentation/device-mapper/dm-init.txt b/Documentation/device-mapper/dm-init.txt
new file mode 100644
index 0000000000000000000000000000000000000000..8464ee7c01b82256d01559994d33cb6676c0c5a3
--- /dev/null
+++ b/Documentation/device-mapper/dm-init.txt
@@ -0,0 +1,114 @@
+Early creation of mapped devices
+====================================
+
+It is possible to configure a device-mapper device to act as the root device for
+your system in two ways.
+
+The first is to build an initial ramdisk which boots to a minimal userspace
+which configures the device, then pivot_root(8) in to it.
+
+The second is to create one or more device-mappers using the module parameter
+"dm-mod.create=" through the kernel boot command line argument.
+
+The format is specified as a string of data separated by commas and optionally
+semi-colons, where:
+ - a comma is used to separate fields like name, uuid, flags and table
+   (specifies one device)
+ - a semi-colon is used to separate devices.
+
+So the format will look like this:
+
+ dm-mod.create=<name>,<uuid>,<minor>,<flags>,<table>[,<table>+][;<name>,<uuid>,<minor>,<flags>,<table>[,<table>+]+]
+
+Where,
+	<name>		::= The device name.
+	<uuid>		::= xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx | ""
+	<minor>		::= The device minor number | ""
+	<flags>		::= "ro" | "rw"
+	<table>		::= <start_sector> <num_sectors> <target_type> <target_args>
+	<target_type>	::= "verity" | "linear" | ... (see list below)
+
+The dm line should be equivalent to the one used by the dmsetup tool with the
+--concise argument.
+
+Target types
+============
+
+Not all target types are available as there are serious risks in allowing
+activation of certain DM targets without first using userspace tools to check
+the validity of associated metadata.
+
+	"cache":		constrained, userspace should verify cache device
+	"crypt":		allowed
+	"delay":		allowed
+	"era":			constrained, userspace should verify metadata device
+	"flakey":		constrained, meant for test
+	"linear":		allowed
+	"log-writes":		constrained, userspace should verify metadata device
+	"mirror":		constrained, userspace should verify main/mirror device
+	"raid":			constrained, userspace should verify metadata device
+	"snapshot":		constrained, userspace should verify src/dst device
+	"snapshot-origin":	allowed
+	"snapshot-merge":	constrained, userspace should verify src/dst device
+	"striped":		allowed
+	"switch":		constrained, userspace should verify dev path
+	"thin":			constrained, requires dm target message from userspace
+	"thin-pool":		constrained, requires dm target message from userspace
+	"verity":		allowed
+	"writecache":		constrained, userspace should verify cache device
+	"zero":			constrained, not meant for rootfs
+
+If the target is not listed above, it is constrained by default (not tested).
+
+Examples
+========
+An example of booting to a linear array made up of user-mode linux block
+devices:
+
+  dm-mod.create="lroot,,,rw, 0 4096 linear 98:16 0, 4096 4096 linear 98:32 0" root=/dev/dm-0
+
+This will boot to a rw dm-linear target of 8192 sectors split across two block
+devices identified by their major:minor numbers.  After boot, udev will rename
+this target to /dev/mapper/lroot (depending on the rules). No uuid was assigned.
+
+An example of multiple device-mappers, with the dm-mod.create="..." contents is shown here
+split on multiple lines for readability:
+
+  vroot,,,ro,
+    0 1740800 verity 254:0 254:0 1740800 sha1
+      76e9be054b15884a9fa85973e9cb274c93afadb6
+      5b3549d54d6c7a3837b9b81ed72e49463a64c03680c47835bef94d768e5646fe;
+  vram,,,rw,
+    0 32768 linear 1:0 0,
+    32768 32768 linear 1:1 0
+
+Other examples (per target):
+
+"crypt":
+  dm-crypt,,8,ro,
+    0 1048576 crypt aes-xts-plain64
+    babebabebabebabebabebabebabebabebabebabebabebabebabebabebabebabe 0
+    /dev/sda 0 1 allow_discards
+
+"delay":
+  dm-delay,,4,ro,0 409600 delay /dev/sda1 0 500
+
+"linear":
+  dm-linear,,,rw,
+    0 32768 linear /dev/sda1 0,
+    32768 1024000 linear /dev/sda2 0,
+    1056768 204800 linear /dev/sda3 0,
+    1261568 512000 linear /dev/sda4 0
+
+"snapshot-origin":
+  dm-snap-orig,,4,ro,0 409600 snapshot-origin 8:2
+
+"striped":
+  dm-striped,,4,ro,0 1638400 striped 4 4096
+  /dev/sda1 0 /dev/sda2 0 /dev/sda3 0 /dev/sda4 0
+
+"verity":
+  dm-verity,,4,ro,
+    0 1638400 verity 1 8:1 8:2 4096 4096 204800 1 sha256
+    fb1a5a0f00deb908d8b53cb270858975e76cf64105d412ce764225d53b8f3cfd
+    51934789604d1b92399c52e7cb149d1b3a1b74bbbcb103b2a0aaacbed5c08584
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 3db222509e44b456acb46fd2defc1a7978299b8e..2557f198e1750002a1a2d7dacd3fefbb926a7fd7 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -436,6 +436,18 @@ config DM_DELAY
 
 	If unsure, say N.
 
+config DM_INIT
+	bool "DM \"dm-mod.create=\" parameter support"
+	depends on BLK_DEV_DM=y
+	---help---
+	Enable "dm-mod.create=" parameter to create mapped devices at init time.
+	This option is useful to allow mounting rootfs without requiring an
+	initramfs.
+	See Documentation/device-mapper/dm-init.txt for dm-mod.create="..."
+	format.
+
+	If unsure, say N.
+
 config DM_UEVENT
 	bool "DM uevents"
 	depends on BLK_DEV_DM
diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index 822f4e8753bc4b197b93a90df936bd0eeeff464a..a52b703e588e23dfa3a240f8882acc2d1eb29212 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -69,6 +69,10 @@ obj-$(CONFIG_DM_INTEGRITY)	+= dm-integrity.o
 obj-$(CONFIG_DM_ZONED)		+= dm-zoned.o
 obj-$(CONFIG_DM_WRITECACHE)	+= dm-writecache.o
 
+ifeq ($(CONFIG_DM_INIT),y)
+dm-mod-objs			+= dm-init.o
+endif
+
 ifeq ($(CONFIG_DM_UEVENT),y)
 dm-mod-objs			+= dm-uevent.o
 endif
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index b29a8327eed15641df9000e019c82ad5c1cffedc..d249cf8ac277e4246d8f398c8aa3b2e46fe90724 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -353,6 +353,7 @@ struct cache_features {
 	enum cache_metadata_mode mode;
 	enum cache_io_mode io_mode;
 	unsigned metadata_version;
+	bool discard_passdown:1;
 };
 
 struct cache_stats {
@@ -1899,7 +1900,11 @@ static bool process_discard_bio(struct cache *cache, struct bio *bio)
 		b = to_dblock(from_dblock(b) + 1);
 	}
 
-	bio_endio(bio);
+	if (cache->features.discard_passdown) {
+		remap_to_origin(cache, bio);
+		generic_make_request(bio);
+	} else
+		bio_endio(bio);
 
 	return false;
 }
@@ -2233,13 +2238,14 @@ static void init_features(struct cache_features *cf)
 	cf->mode = CM_WRITE;
 	cf->io_mode = CM_IO_WRITEBACK;
 	cf->metadata_version = 1;
+	cf->discard_passdown = true;
 }
 
 static int parse_features(struct cache_args *ca, struct dm_arg_set *as,
 			  char **error)
 {
 	static const struct dm_arg _args[] = {
-		{0, 2, "Invalid number of cache feature arguments"},
+		{0, 3, "Invalid number of cache feature arguments"},
 	};
 
 	int r, mode_ctr = 0;
@@ -2274,6 +2280,9 @@ static int parse_features(struct cache_args *ca, struct dm_arg_set *as,
 		else if (!strcasecmp(arg, "metadata2"))
 			cf->metadata_version = 2;
 
+		else if (!strcasecmp(arg, "no_discard_passdown"))
+			cf->discard_passdown = false;
+
 		else {
 			*error = "Unrecognised cache feature requested";
 			return -EINVAL;
@@ -2496,7 +2505,6 @@ static int cache_create(struct cache_args *ca, struct cache **result)
 
 	ti->num_discard_bios = 1;
 	ti->discards_supported = true;
-	ti->split_discard_bios = false;
 
 	ti->per_io_data_size = sizeof(struct per_bio_data);
 
@@ -3120,6 +3128,39 @@ static void cache_resume(struct dm_target *ti)
 	do_waker(&cache->waker.work);
 }
 
+static void emit_flags(struct cache *cache, char *result,
+		       unsigned maxlen, ssize_t *sz_ptr)
+{
+	ssize_t sz = *sz_ptr;
+	struct cache_features *cf = &cache->features;
+	unsigned count = (cf->metadata_version == 2) + !cf->discard_passdown + 1;
+
+	DMEMIT("%u ", count);
+
+	if (cf->metadata_version == 2)
+		DMEMIT("metadata2 ");
+
+	if (writethrough_mode(cache))
+		DMEMIT("writethrough ");
+
+	else if (passthrough_mode(cache))
+		DMEMIT("passthrough ");
+
+	else if (writeback_mode(cache))
+		DMEMIT("writeback ");
+
+	else {
+		DMEMIT("unknown ");
+		DMERR("%s: internal error: unknown io mode: %d",
+		      cache_device_name(cache), (int) cf->io_mode);
+	}
+
+	if (!cf->discard_passdown)
+		DMEMIT("no_discard_passdown ");
+
+	*sz_ptr = sz;
+}
+
 /*
  * Status format:
  *
@@ -3186,25 +3227,7 @@ static void cache_status(struct dm_target *ti, status_type_t type,
 		       (unsigned) atomic_read(&cache->stats.promotion),
 		       (unsigned long) atomic_read(&cache->nr_dirty));
 
-		if (cache->features.metadata_version == 2)
-			DMEMIT("2 metadata2 ");
-		else
-			DMEMIT("1 ");
-
-		if (writethrough_mode(cache))
-			DMEMIT("writethrough ");
-
-		else if (passthrough_mode(cache))
-			DMEMIT("passthrough ");
-
-		else if (writeback_mode(cache))
-			DMEMIT("writeback ");
-
-		else {
-			DMERR("%s: internal error: unknown io mode: %d",
-			      cache_device_name(cache), (int) cache->features.io_mode);
-			goto err;
-		}
+		emit_flags(cache, result, maxlen, &sz);
 
 		DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold);
 
@@ -3433,14 +3456,62 @@ static int cache_iterate_devices(struct dm_target *ti,
 	return r;
 }
 
+static bool origin_dev_supports_discard(struct block_device *origin_bdev)
+{
+	struct request_queue *q = bdev_get_queue(origin_bdev);
+
+	return q && blk_queue_discard(q);
+}
+
+/*
+ * If discard_passdown was enabled verify that the origin device
+ * supports discards.  Disable discard_passdown if not.
+ */
+static void disable_passdown_if_not_supported(struct cache *cache)
+{
+	struct block_device *origin_bdev = cache->origin_dev->bdev;
+	struct queue_limits *origin_limits = &bdev_get_queue(origin_bdev)->limits;
+	const char *reason = NULL;
+	char buf[BDEVNAME_SIZE];
+
+	if (!cache->features.discard_passdown)
+		return;
+
+	if (!origin_dev_supports_discard(origin_bdev))
+		reason = "discard unsupported";
+
+	else if (origin_limits->max_discard_sectors < cache->sectors_per_block)
+		reason = "max discard sectors smaller than a block";
+
+	if (reason) {
+		DMWARN("Origin device (%s) %s: Disabling discard passdown.",
+		       bdevname(origin_bdev, buf), reason);
+		cache->features.discard_passdown = false;
+	}
+}
+
 static void set_discard_limits(struct cache *cache, struct queue_limits *limits)
 {
+	struct block_device *origin_bdev = cache->origin_dev->bdev;
+	struct queue_limits *origin_limits = &bdev_get_queue(origin_bdev)->limits;
+
+	if (!cache->features.discard_passdown) {
+		/* No passdown is done so setting own virtual limits */
+		limits->max_discard_sectors = min_t(sector_t, cache->discard_block_size * 1024,
+						    cache->origin_sectors);
+		limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT;
+		return;
+	}
+
 	/*
-	 * FIXME: these limits may be incompatible with the cache device
+	 * cache_iterate_devices() is stacking both origin and fast device limits
+	 * but discards aren't passed to fast device, so inherit origin's limits.
 	 */
-	limits->max_discard_sectors = min_t(sector_t, cache->discard_block_size * 1024,
-					    cache->origin_sectors);
-	limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT;
+	limits->max_discard_sectors = origin_limits->max_discard_sectors;
+	limits->max_hw_discard_sectors = origin_limits->max_hw_discard_sectors;
+	limits->discard_granularity = origin_limits->discard_granularity;
+	limits->discard_alignment = origin_limits->discard_alignment;
+	limits->discard_misaligned = origin_limits->discard_misaligned;
 }
 
 static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits)
@@ -3457,6 +3528,8 @@ static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits)
 		blk_limits_io_min(limits, cache->sectors_per_block << SECTOR_SHIFT);
 		blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT);
 	}
+
+	disable_passdown_if_not_supported(cache);
 	set_discard_limits(cache, limits);
 }
 
@@ -3464,7 +3537,7 @@ static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits)
 
 static struct target_type cache_target = {
 	.name = "cache",
-	.version = {2, 0, 0},
+	.version = {2, 1, 0},
 	.module = THIS_MODULE,
 	.ctr = cache_ctr,
 	.dtr = cache_dtr,
diff --git a/drivers/md/dm-init.c b/drivers/md/dm-init.c
new file mode 100644
index 0000000000000000000000000000000000000000..b53f30f16b4d4f2c02bf9c15e5b801234b8cd9ae
--- /dev/null
+++ b/drivers/md/dm-init.c
@@ -0,0 +1,303 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * dm-init.c
+ * Copyright (C) 2017 The Chromium OS Authors <chromium-os-dev@chromium.org>
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/ctype.h>
+#include <linux/device.h>
+#include <linux/device-mapper.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/moduleparam.h>
+
+#define DM_MSG_PREFIX "init"
+#define DM_MAX_DEVICES 256
+#define DM_MAX_TARGETS 256
+#define DM_MAX_STR_SIZE 4096
+
+static char *create;
+
+/*
+ * Format: dm-mod.create=<name>,<uuid>,<minor>,<flags>,<table>[,<table>+][;<name>,<uuid>,<minor>,<flags>,<table>[,<table>+]+]
+ * Table format: <start_sector> <num_sectors> <target_type> <target_args>
+ *
+ * See Documentation/device-mapper/dm-init.txt for dm-mod.create="..." format
+ * details.
+ */
+
+struct dm_device {
+	struct dm_ioctl dmi;
+	struct dm_target_spec *table[DM_MAX_TARGETS];
+	char *target_args_array[DM_MAX_TARGETS];
+	struct list_head list;
+};
+
+const char *dm_allowed_targets[] __initconst = {
+	"crypt",
+	"delay",
+	"linear",
+	"snapshot-origin",
+	"striped",
+	"verity",
+};
+
+static int __init dm_verify_target_type(const char *target)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(dm_allowed_targets); i++) {
+		if (!strcmp(dm_allowed_targets[i], target))
+			return 0;
+	}
+	return -EINVAL;
+}
+
+static void __init dm_setup_cleanup(struct list_head *devices)
+{
+	struct dm_device *dev, *tmp;
+	unsigned int i;
+
+	list_for_each_entry_safe(dev, tmp, devices, list) {
+		list_del(&dev->list);
+		for (i = 0; i < dev->dmi.target_count; i++) {
+			kfree(dev->table[i]);
+			kfree(dev->target_args_array[i]);
+		}
+		kfree(dev);
+	}
+}
+
+/**
+ * str_field_delimit - delimit a string based on a separator char.
+ * @str: the pointer to the string to delimit.
+ * @separator: char that delimits the field
+ *
+ * Find a @separator and replace it by '\0'.
+ * Remove leading and trailing spaces.
+ * Return the remainder string after the @separator.
+ */
+static char __init *str_field_delimit(char **str, char separator)
+{
+	char *s;
+
+	/* TODO: add support for escaped characters */
+	*str = skip_spaces(*str);
+	s = strchr(*str, separator);
+	/* Delimit the field and remove trailing spaces */
+	if (s)
+		*s = '\0';
+	*str = strim(*str);
+	return s ? ++s : NULL;
+}
+
+/**
+ * dm_parse_table_entry - parse a table entry
+ * @dev: device to store the parsed information.
+ * @str: the pointer to a string with the format:
+ *	<start_sector> <num_sectors> <target_type> <target_args>[, ...]
+ *
+ * Return the remainder string after the table entry, i.e, after the comma which
+ * delimits the entry or NULL if reached the end of the string.
+ */
+static char __init *dm_parse_table_entry(struct dm_device *dev, char *str)
+{
+	const unsigned int n = dev->dmi.target_count - 1;
+	struct dm_target_spec *sp;
+	unsigned int i;
+	/* fields:  */
+	char *field[4];
+	char *next;
+
+	field[0] = str;
+	/* Delimit first 3 fields that are separated by space */
+	for (i = 0; i < ARRAY_SIZE(field) - 1; i++) {
+		field[i + 1] = str_field_delimit(&field[i], ' ');
+		if (!field[i + 1])
+			return ERR_PTR(-EINVAL);
+	}
+	/* Delimit last field that can be terminated by comma */
+	next = str_field_delimit(&field[i], ',');
+
+	sp = kzalloc(sizeof(*sp), GFP_KERNEL);
+	if (!sp)
+		return ERR_PTR(-ENOMEM);
+	dev->table[n] = sp;
+
+	/* start_sector */
+	if (kstrtoull(field[0], 0, &sp->sector_start))
+		return ERR_PTR(-EINVAL);
+	/* num_sector */
+	if (kstrtoull(field[1], 0, &sp->length))
+		return ERR_PTR(-EINVAL);
+	/* target_type */
+	strscpy(sp->target_type, field[2], sizeof(sp->target_type));
+	if (dm_verify_target_type(sp->target_type)) {
+		DMERR("invalid type \"%s\"", sp->target_type);
+		return ERR_PTR(-EINVAL);
+	}
+	/* target_args */
+	dev->target_args_array[n] = kstrndup(field[3], GFP_KERNEL,
+					     DM_MAX_STR_SIZE);
+	if (!dev->target_args_array[n])
+		return ERR_PTR(-ENOMEM);
+
+	return next;
+}
+
+/**
+ * dm_parse_table - parse "dm-mod.create=" table field
+ * @dev: device to store the parsed information.
+ * @str: the pointer to a string with the format:
+ *	<table>[,<table>+]
+ */
+static int __init dm_parse_table(struct dm_device *dev, char *str)
+{
+	char *table_entry = str;
+
+	while (table_entry) {
+		DMDEBUG("parsing table \"%s\"", str);
+		if (++dev->dmi.target_count >= DM_MAX_TARGETS) {
+			DMERR("too many targets %u > %d",
+			      dev->dmi.target_count, DM_MAX_TARGETS);
+			return -EINVAL;
+		}
+		table_entry = dm_parse_table_entry(dev, table_entry);
+		if (IS_ERR(table_entry)) {
+			DMERR("couldn't parse table");
+			return PTR_ERR(table_entry);
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * dm_parse_device_entry - parse a device entry
+ * @dev: device to store the parsed information.
+ * @str: the pointer to a string with the format:
+ *	name,uuid,minor,flags,table[; ...]
+ *
+ * Return the remainder string after the table entry, i.e, after the semi-colon
+ * which delimits the entry or NULL if reached the end of the string.
+ */
+static char __init *dm_parse_device_entry(struct dm_device *dev, char *str)
+{
+	/* There are 5 fields: name,uuid,minor,flags,table; */
+	char *field[5];
+	unsigned int i;
+	char *next;
+
+	field[0] = str;
+	/* Delimit first 4 fields that are separated by comma */
+	for (i = 0; i < ARRAY_SIZE(field) - 1; i++) {
+		field[i+1] = str_field_delimit(&field[i], ',');
+		if (!field[i+1])
+			return ERR_PTR(-EINVAL);
+	}
+	/* Delimit last field that can be delimited by semi-colon */
+	next = str_field_delimit(&field[i], ';');
+
+	/* name */
+	strscpy(dev->dmi.name, field[0], sizeof(dev->dmi.name));
+	/* uuid */
+	strscpy(dev->dmi.uuid, field[1], sizeof(dev->dmi.uuid));
+	/* minor */
+	if (strlen(field[2])) {
+		if (kstrtoull(field[2], 0, &dev->dmi.dev))
+			return ERR_PTR(-EINVAL);
+		dev->dmi.flags |= DM_PERSISTENT_DEV_FLAG;
+	}
+	/* flags */
+	if (!strcmp(field[3], "ro"))
+		dev->dmi.flags |= DM_READONLY_FLAG;
+	else if (strcmp(field[3], "rw"))
+		return ERR_PTR(-EINVAL);
+	/* table */
+	if (dm_parse_table(dev, field[4]))
+		return ERR_PTR(-EINVAL);
+
+	return next;
+}
+
+/**
+ * dm_parse_devices - parse "dm-mod.create=" argument
+ * @devices: list of struct dm_device to store the parsed information.
+ * @str: the pointer to a string with the format:
+ *	<device>[;<device>+]
+ */
+static int __init dm_parse_devices(struct list_head *devices, char *str)
+{
+	unsigned long ndev = 0;
+	struct dm_device *dev;
+	char *device = str;
+
+	DMDEBUG("parsing \"%s\"", str);
+	while (device) {
+		dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+		if (!dev)
+			return -ENOMEM;
+		list_add_tail(&dev->list, devices);
+
+		if (++ndev >= DM_MAX_DEVICES) {
+			DMERR("too many targets %u > %d",
+			      dev->dmi.target_count, DM_MAX_TARGETS);
+			return -EINVAL;
+		}
+
+		device = dm_parse_device_entry(dev, device);
+		if (IS_ERR(device)) {
+			DMERR("couldn't parse device");
+			return PTR_ERR(device);
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * dm_init_init - parse "dm-mod.create=" argument and configure drivers
+ */
+static int __init dm_init_init(void)
+{
+	struct dm_device *dev;
+	LIST_HEAD(devices);
+	char *str;
+	int r;
+
+	if (!create)
+		return 0;
+
+	if (strlen(create) >= DM_MAX_STR_SIZE) {
+		DMERR("Argument is too big. Limit is %d\n", DM_MAX_STR_SIZE);
+		return -EINVAL;
+	}
+	str = kstrndup(create, GFP_KERNEL, DM_MAX_STR_SIZE);
+	if (!str)
+		return -ENOMEM;
+
+	r = dm_parse_devices(&devices, str);
+	if (r)
+		goto out;
+
+	DMINFO("waiting for all devices to be available before creating mapped devices\n");
+	wait_for_device_probe();
+
+	list_for_each_entry(dev, &devices, list) {
+		if (dm_early_create(&dev->dmi, dev->table,
+				    dev->target_args_array))
+			break;
+	}
+out:
+	kfree(str);
+	dm_setup_cleanup(&devices);
+	return r;
+}
+
+late_initcall(dm_init_init);
+
+module_param(create, charp, 0);
+MODULE_PARM_DESC(create, "Create a mapped device in early boot");
diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index 457200ca62878ee87b0cd5127540597454e7bbd9..d57d997a52c81cfe6c68918520316f993aeebc44 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -1122,7 +1122,7 @@ static int dm_integrity_rw_tag(struct dm_integrity_c *ic, unsigned char *tag, se
 			return r;
 
 		data = dm_bufio_read(ic->bufio, *metadata_block, &b);
-		if (unlikely(IS_ERR(data)))
+		if (IS_ERR(data))
 			return PTR_ERR(data);
 
 		to_copy = min((1U << SECTOR_SHIFT << ic->log2_buffer_sectors) - *metadata_offset, total_size);
@@ -1368,8 +1368,8 @@ static void integrity_metadata(struct work_struct *w)
 						checksums_ptr - checksums, !dio->write ? TAG_CMP : TAG_WRITE);
 			if (unlikely(r)) {
 				if (r > 0) {
-					DMERR("Checksum failed at sector 0x%llx",
-					      (unsigned long long)(sector - ((r + ic->tag_size - 1) / ic->tag_size)));
+					DMERR_LIMIT("Checksum failed at sector 0x%llx",
+						    (unsigned long long)(sector - ((r + ic->tag_size - 1) / ic->tag_size)));
 					r = -EILSEQ;
 					atomic64_inc(&ic->number_of_mismatches);
 				}
@@ -1561,8 +1561,8 @@ static bool __journal_read_write(struct dm_integrity_io *dio, struct bio *bio,
 
 					integrity_sector_checksum(ic, logical_sector, mem + bv.bv_offset, checksums_onstack);
 					if (unlikely(memcmp(checksums_onstack, journal_entry_tag(ic, je), ic->tag_size))) {
-						DMERR("Checksum failed when reading from journal, at sector 0x%llx",
-						      (unsigned long long)logical_sector);
+						DMERR_LIMIT("Checksum failed when reading from journal, at sector 0x%llx",
+							    (unsigned long long)logical_sector);
 					}
 				}
 #endif
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index f666778ad23728cdc323f7570d837ebb30ede660..c740153b4e52df15ee7b4cab6c9b1e83d897143f 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -2018,3 +2018,106 @@ int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid)
 
 	return r;
 }
+
+
+/**
+ * dm_early_create - create a mapped device in early boot.
+ *
+ * @dmi: Contains main information of the device mapping to be created.
+ * @spec_array: array of pointers to struct dm_target_spec. Describes the
+ * mapping table of the device.
+ * @target_params_array: array of strings with the parameters to a specific
+ * target.
+ *
+ * Instead of having the struct dm_target_spec and the parameters for every
+ * target embedded at the end of struct dm_ioctl (as performed in a normal
+ * ioctl), pass them as arguments, so the caller doesn't need to serialize them.
+ * The size of the spec_array and target_params_array is given by
+ * @dmi->target_count.
+ * This function is supposed to be called in early boot, so locking mechanisms
+ * to protect against concurrent loads are not required.
+ */
+int __init dm_early_create(struct dm_ioctl *dmi,
+			   struct dm_target_spec **spec_array,
+			   char **target_params_array)
+{
+	int r, m = DM_ANY_MINOR;
+	struct dm_table *t, *old_map;
+	struct mapped_device *md;
+	unsigned int i;
+
+	if (!dmi->target_count)
+		return -EINVAL;
+
+	r = check_name(dmi->name);
+	if (r)
+		return r;
+
+	if (dmi->flags & DM_PERSISTENT_DEV_FLAG)
+		m = MINOR(huge_decode_dev(dmi->dev));
+
+	/* alloc dm device */
+	r = dm_create(m, &md);
+	if (r)
+		return r;
+
+	/* hash insert */
+	r = dm_hash_insert(dmi->name, *dmi->uuid ? dmi->uuid : NULL, md);
+	if (r)
+		goto err_destroy_dm;
+
+	/* alloc table */
+	r = dm_table_create(&t, get_mode(dmi), dmi->target_count, md);
+	if (r)
+		goto err_destroy_dm;
+
+	/* add targets */
+	for (i = 0; i < dmi->target_count; i++) {
+		r = dm_table_add_target(t, spec_array[i]->target_type,
+					(sector_t) spec_array[i]->sector_start,
+					(sector_t) spec_array[i]->length,
+					target_params_array[i]);
+		if (r) {
+			DMWARN("error adding target to table");
+			goto err_destroy_table;
+		}
+	}
+
+	/* finish table */
+	r = dm_table_complete(t);
+	if (r)
+		goto err_destroy_table;
+
+	md->type = dm_table_get_type(t);
+	/* setup md->queue to reflect md's type (may block) */
+	r = dm_setup_md_queue(md, t);
+	if (r) {
+		DMWARN("unable to set up device queue for new table.");
+		goto err_destroy_table;
+	}
+
+	/* Set new map */
+	dm_suspend(md, 0);
+	old_map = dm_swap_table(md, t);
+	if (IS_ERR(old_map)) {
+		r = PTR_ERR(old_map);
+		goto err_destroy_table;
+	}
+	set_disk_ro(dm_disk(md), !!(dmi->flags & DM_READONLY_FLAG));
+
+	/* resume device */
+	r = dm_resume(md);
+	if (r)
+		goto err_destroy_table;
+
+	DMINFO("%s (%s) is ready", md->disk->disk_name, dmi->name);
+	dm_put(md);
+	return 0;
+
+err_destroy_table:
+	dm_table_destroy(t);
+err_destroy_dm:
+	dm_put(md);
+	dm_destroy(md);
+	return r;
+}
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index adcfe8ae10aa78c521e77bc4c71d077c43e284c3..9fdef6897316fe6ee2eab0d36f50c0e870c73304 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -2986,11 +2986,6 @@ static void configure_discard_support(struct raid_set *rs)
 		}
 	}
 
-	/*
-	 * RAID1 and RAID10 personalities require bio splitting,
-	 * RAID0/4/5/6 don't and process large discard bios properly.
-	 */
-	ti->split_discard_bios = !!(rs_is_raid1(rs) || rs_is_raid10(rs));
 	ti->num_discard_bios = 1;
 }
 
@@ -3747,6 +3742,15 @@ static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
 
 	blk_limits_io_min(limits, chunk_size);
 	blk_limits_io_opt(limits, chunk_size * mddev_data_stripes(rs));
+
+	/*
+	 * RAID1 and RAID10 personalities require bio splitting,
+	 * RAID0/4/5/6 don't and process large discard bios properly.
+	 */
+	if (rs_is_raid1(rs) || rs_is_raid10(rs)) {
+		limits->discard_granularity = chunk_size;
+		limits->max_discard_sectors = chunk_size;
+	}
 }
 
 static void raid_postsuspend(struct dm_target *ti)
diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
index b2c03c079a8db21eb19ec264a0760598e84624bf..09773636602d3d86728b127ddb67b2d674b67cae 100644
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -12,6 +12,22 @@
 
 #define DM_MSG_PREFIX "core-rq"
 
+/*
+ * One of these is allocated per request.
+ */
+struct dm_rq_target_io {
+	struct mapped_device *md;
+	struct dm_target *ti;
+	struct request *orig, *clone;
+	struct kthread_work work;
+	blk_status_t error;
+	union map_info info;
+	struct dm_stats_aux stats_aux;
+	unsigned long duration_jiffies;
+	unsigned n_sectors;
+	unsigned completed;
+};
+
 #define DM_MQ_NR_HW_QUEUES 1
 #define DM_MQ_QUEUE_DEPTH 2048
 static unsigned dm_mq_nr_hw_queues = DM_MQ_NR_HW_QUEUES;
diff --git a/drivers/md/dm-rq.h b/drivers/md/dm-rq.h
index b39245545229fbb19e51caf35d969c5633f65125..1eea0da641db55838912fc541f4b93506094fc9c 100644
--- a/drivers/md/dm-rq.h
+++ b/drivers/md/dm-rq.h
@@ -16,22 +16,6 @@
 
 struct mapped_device;
 
-/*
- * One of these is allocated per request.
- */
-struct dm_rq_target_io {
-	struct mapped_device *md;
-	struct dm_target *ti;
-	struct request *orig, *clone;
-	struct kthread_work work;
-	blk_status_t error;
-	union map_info info;
-	struct dm_stats_aux stats_aux;
-	unsigned long duration_jiffies;
-	unsigned n_sectors;
-	unsigned completed;
-};
-
 /*
  * For request-based dm - the bio clones we allocate are embedded in these
  * structs.
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 36805b12661e173be5d2a845626f82baaf8de690..a168963b757df4fe12c885c48456a50d586851fe 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -2338,13 +2338,6 @@ static int origin_map(struct dm_target *ti, struct bio *bio)
 	return do_origin(o->dev, bio);
 }
 
-static long origin_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
-		long nr_pages, void **kaddr, pfn_t *pfn)
-{
-	DMWARN("device does not support dax.");
-	return -EIO;
-}
-
 /*
  * Set the target "max_io_len" field to the minimum of all the snapshots'
  * chunk sizes.
@@ -2404,7 +2397,6 @@ static struct target_type origin_target = {
 	.postsuspend = origin_postsuspend,
 	.status  = origin_status,
 	.iterate_devices = origin_iterate_devices,
-	.direct_access = origin_dax_direct_access,
 };
 
 static struct target_type snapshot_target = {
diff --git a/drivers/md/dm-switch.c b/drivers/md/dm-switch.c
index fae35caf367208ab22cbe6900010ee353f52d666..8a0f057b81220288afd70404ab83d8a5c10cefcf 100644
--- a/drivers/md/dm-switch.c
+++ b/drivers/md/dm-switch.c
@@ -61,8 +61,7 @@ static struct switch_ctx *alloc_switch_ctx(struct dm_target *ti, unsigned nr_pat
 {
 	struct switch_ctx *sctx;
 
-	sctx = kzalloc(sizeof(struct switch_ctx) + nr_paths * sizeof(struct switch_path),
-		       GFP_KERNEL);
+	sctx = kzalloc(struct_size(sctx, path_list, nr_paths), GFP_KERNEL);
 	if (!sctx)
 		return NULL;
 
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index e83b63608262ac46bf4fa0f8f869294de6bdf22f..fcd887703f953eebbfb7cc2e1aee9cd82113e5c9 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -3283,6 +3283,13 @@ static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	as.argc = argc;
 	as.argv = argv;
 
+	/* make sure metadata and data are different devices */
+	if (!strcmp(argv[0], argv[1])) {
+		ti->error = "Error setting metadata or data device";
+		r = -EINVAL;
+		goto out_unlock;
+	}
+
 	/*
 	 * Set default pool features.
 	 */
@@ -4167,6 +4174,12 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	tc->sort_bio_list = RB_ROOT;
 
 	if (argc == 3) {
+		if (!strcmp(argv[0], argv[2])) {
+			ti->error = "Error setting origin device";
+			r = -EINVAL;
+			goto bad_origin_dev;
+		}
+
 		r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
 		if (r) {
 			ti->error = "Error opening origin device";
@@ -4227,7 +4240,6 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	if (tc->pool->pf.discard_enabled) {
 		ti->discards_supported = true;
 		ti->num_discard_bios = 1;
-		ti->split_discard_bios = false;
 	}
 
 	mutex_unlock(&dm_thin_pool_table.mutex);
diff --git a/drivers/md/dm-verity-fec.c b/drivers/md/dm-verity-fec.c
index 0ce04e5b4afbaba8b53a145ae20d1652f1c75de7..b634fa23f4c46374afb8a05636b90492d4ad2101 100644
--- a/drivers/md/dm-verity-fec.c
+++ b/drivers/md/dm-verity-fec.c
@@ -73,7 +73,7 @@ static u8 *fec_read_parity(struct dm_verity *v, u64 rsb, int index,
 	*offset = (unsigned)(position - (block << v->data_dev_block_bits));
 
 	res = dm_bufio_read(v->fec->bufio, v->fec->start + block, buf);
-	if (unlikely(IS_ERR(res))) {
+	if (IS_ERR(res)) {
 		DMERR("%s: FEC %llu: parity read failed (block %llu): %ld",
 		      v->data_dev->name, (unsigned long long)rsb,
 		      (unsigned long long)(v->fec->start + block),
@@ -163,7 +163,7 @@ static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio,
 			dm_bufio_release(buf);
 
 			par = fec_read_parity(v, rsb, block_offset, &offset, &buf);
-			if (unlikely(IS_ERR(par)))
+			if (IS_ERR(par))
 				return PTR_ERR(par);
 		}
 	}
@@ -253,7 +253,7 @@ static int fec_read_bufs(struct dm_verity *v, struct dm_verity_io *io,
 		}
 
 		bbuf = dm_bufio_read(bufio, block, &buf);
-		if (unlikely(IS_ERR(bbuf))) {
+		if (IS_ERR(bbuf)) {
 			DMWARN_LIMIT("%s: FEC %llu: read failed (%llu): %ld",
 				     v->data_dev->name,
 				     (unsigned long long)rsb,
diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index 2b8cee35e4d5a90daff8cc3e17a9cc3d0c90af83..f7822875589ea8439764d72a488adc2846a28f6f 100644
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -1859,7 +1859,7 @@ static int writecache_ctr(struct dm_target *ti, unsigned argc, char **argv)
 		goto bad;
 	}
 
-	wc->writeback_wq = alloc_workqueue("writecache-writeabck", WQ_MEM_RECLAIM, 1);
+	wc->writeback_wq = alloc_workqueue("writecache-writeback", WQ_MEM_RECLAIM, 1);
 	if (!wc->writeback_wq) {
 		r = -ENOMEM;
 		ti->error = "Could not allocate writeback workqueue";
diff --git a/drivers/md/dm-zoned-target.c b/drivers/md/dm-zoned-target.c
index 6af5babe6837605c7a25983ef61fb7d83e73af30..8865c1709e16357178ede5284c4477536bf2369d 100644
--- a/drivers/md/dm-zoned-target.c
+++ b/drivers/md/dm-zoned-target.c
@@ -727,7 +727,6 @@ static int dmz_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	ti->per_io_data_size = sizeof(struct dmz_bioctx);
 	ti->flush_supported = true;
 	ti->discards_supported = true;
-	ti->split_discard_bios = true;
 
 	/* The exposed capacity is the number of chunks that can be mapped */
 	ti->len = (sector_t)dmz_nr_chunks(dmz->metadata) << dev->zone_nr_sectors_shift;
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 515e6af9bed2c7ab5e94e356215020422316a3ce..68d24056d0b1c17d7fa0c271d1d5582d7eb72c89 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -158,9 +158,6 @@ struct table_device {
 	struct dm_dev dm_dev;
 };
 
-static struct kmem_cache *_rq_tio_cache;
-static struct kmem_cache *_rq_cache;
-
 /*
  * Bio-based DM's mempools' reserved IOs set by the user.
  */
@@ -222,20 +219,11 @@ static unsigned dm_get_numa_node(void)
 
 static int __init local_init(void)
 {
-	int r = -ENOMEM;
-
-	_rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0);
-	if (!_rq_tio_cache)
-		return r;
-
-	_rq_cache = kmem_cache_create("dm_old_clone_request", sizeof(struct request),
-				      __alignof__(struct request), 0, NULL);
-	if (!_rq_cache)
-		goto out_free_rq_tio_cache;
+	int r;
 
 	r = dm_uevent_init();
 	if (r)
-		goto out_free_rq_cache;
+		return r;
 
 	deferred_remove_workqueue = alloc_workqueue("kdmremove", WQ_UNBOUND, 1);
 	if (!deferred_remove_workqueue) {
@@ -257,10 +245,6 @@ static int __init local_init(void)
 	destroy_workqueue(deferred_remove_workqueue);
 out_uevent_exit:
 	dm_uevent_exit();
-out_free_rq_cache:
-	kmem_cache_destroy(_rq_cache);
-out_free_rq_tio_cache:
-	kmem_cache_destroy(_rq_tio_cache);
 
 	return r;
 }
@@ -270,8 +254,6 @@ static void local_exit(void)
 	flush_scheduled_work();
 	destroy_workqueue(deferred_remove_workqueue);
 
-	kmem_cache_destroy(_rq_cache);
-	kmem_cache_destroy(_rq_tio_cache);
 	unregister_blkdev(_major, _name);
 	dm_uevent_exit();
 
@@ -1478,17 +1460,10 @@ static unsigned get_num_write_zeroes_bios(struct dm_target *ti)
 	return ti->num_write_zeroes_bios;
 }
 
-typedef bool (*is_split_required_fn)(struct dm_target *ti);
-
-static bool is_split_required_for_discard(struct dm_target *ti)
-{
-	return ti->split_discard_bios;
-}
-
 static int __send_changing_extent_only(struct clone_info *ci, struct dm_target *ti,
-				       unsigned num_bios, bool is_split_required)
+				       unsigned num_bios)
 {
-	unsigned len;
+	unsigned len = ci->sector_count;
 
 	/*
 	 * Even though the device advertised support for this type of
@@ -1499,11 +1474,6 @@ static int __send_changing_extent_only(struct clone_info *ci, struct dm_target *
 	if (!num_bios)
 		return -EOPNOTSUPP;
 
-	if (!is_split_required)
-		len = min((sector_t)ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
-	else
-		len = min((sector_t)ci->sector_count, max_io_len(ci->sector, ti));
-
 	__send_duplicate_bios(ci, ti, num_bios, &len);
 
 	ci->sector += len;
@@ -1514,23 +1484,38 @@ static int __send_changing_extent_only(struct clone_info *ci, struct dm_target *
 
 static int __send_discard(struct clone_info *ci, struct dm_target *ti)
 {
-	return __send_changing_extent_only(ci, ti, get_num_discard_bios(ti),
-					   is_split_required_for_discard(ti));
+	return __send_changing_extent_only(ci, ti, get_num_discard_bios(ti));
 }
 
 static int __send_secure_erase(struct clone_info *ci, struct dm_target *ti)
 {
-	return __send_changing_extent_only(ci, ti, get_num_secure_erase_bios(ti), false);
+	return __send_changing_extent_only(ci, ti, get_num_secure_erase_bios(ti));
 }
 
 static int __send_write_same(struct clone_info *ci, struct dm_target *ti)
 {
-	return __send_changing_extent_only(ci, ti, get_num_write_same_bios(ti), false);
+	return __send_changing_extent_only(ci, ti, get_num_write_same_bios(ti));
 }
 
 static int __send_write_zeroes(struct clone_info *ci, struct dm_target *ti)
 {
-	return __send_changing_extent_only(ci, ti, get_num_write_zeroes_bios(ti), false);
+	return __send_changing_extent_only(ci, ti, get_num_write_zeroes_bios(ti));
+}
+
+static bool is_abnormal_io(struct bio *bio)
+{
+	bool r = false;
+
+	switch (bio_op(bio)) {
+	case REQ_OP_DISCARD:
+	case REQ_OP_SECURE_ERASE:
+	case REQ_OP_WRITE_SAME:
+	case REQ_OP_WRITE_ZEROES:
+		r = true;
+		break;
+	}
+
+	return r;
 }
 
 static bool __process_abnormal_io(struct clone_info *ci, struct dm_target *ti,
@@ -1565,7 +1550,7 @@ static int __split_and_process_non_flush(struct clone_info *ci)
 	if (!dm_target_is_valid(ti))
 		return -EIO;
 
-	if (unlikely(__process_abnormal_io(ci, ti, &r)))
+	if (__process_abnormal_io(ci, ti, &r))
 		return r;
 
 	len = min_t(sector_t, max_io_len(ci->sector, ti), ci->sector_count);
@@ -1601,13 +1586,6 @@ static blk_qc_t __split_and_process_bio(struct mapped_device *md,
 	blk_qc_t ret = BLK_QC_T_NONE;
 	int error = 0;
 
-	if (unlikely(!map)) {
-		bio_io_error(bio);
-		return ret;
-	}
-
-	blk_queue_split(md->queue, &bio);
-
 	init_clone_info(&ci, md, map, bio);
 
 	if (bio->bi_opf & REQ_PREFLUSH) {
@@ -1675,18 +1653,13 @@ static blk_qc_t __split_and_process_bio(struct mapped_device *md,
  * Optimized variant of __split_and_process_bio that leverages the
  * fact that targets that use it do _not_ have a need to split bios.
  */
-static blk_qc_t __process_bio(struct mapped_device *md,
-			      struct dm_table *map, struct bio *bio)
+static blk_qc_t __process_bio(struct mapped_device *md, struct dm_table *map,
+			      struct bio *bio, struct dm_target *ti)
 {
 	struct clone_info ci;
 	blk_qc_t ret = BLK_QC_T_NONE;
 	int error = 0;
 
-	if (unlikely(!map)) {
-		bio_io_error(bio);
-		return ret;
-	}
-
 	init_clone_info(&ci, md, map, bio);
 
 	if (bio->bi_opf & REQ_PREFLUSH) {
@@ -1704,21 +1677,11 @@ static blk_qc_t __process_bio(struct mapped_device *md,
 		error = __send_empty_flush(&ci);
 		/* dec_pending submits any data associated with flush */
 	} else {
-		struct dm_target *ti = md->immutable_target;
 		struct dm_target_io *tio;
 
-		/*
-		 * Defend against IO still getting in during teardown
-		 * - as was seen for a time with nvme-fcloop
-		 */
-		if (WARN_ON_ONCE(!ti || !dm_target_is_valid(ti))) {
-			error = -EIO;
-			goto out;
-		}
-
 		ci.bio = bio;
 		ci.sector_count = bio_sectors(bio);
-		if (unlikely(__process_abnormal_io(&ci, ti, &error)))
+		if (__process_abnormal_io(&ci, ti, &error))
 			goto out;
 
 		tio = alloc_tio(&ci, ti, 0, GFP_NOIO);
@@ -1730,11 +1693,55 @@ static blk_qc_t __process_bio(struct mapped_device *md,
 	return ret;
 }
 
+static void dm_queue_split(struct mapped_device *md, struct dm_target *ti, struct bio **bio)
+{
+	unsigned len, sector_count;
+
+	sector_count = bio_sectors(*bio);
+	len = min_t(sector_t, max_io_len((*bio)->bi_iter.bi_sector, ti), sector_count);
+
+	if (sector_count > len) {
+		struct bio *split = bio_split(*bio, len, GFP_NOIO, &md->queue->bio_split);
+
+		bio_chain(split, *bio);
+		trace_block_split(md->queue, split, (*bio)->bi_iter.bi_sector);
+		generic_make_request(*bio);
+		*bio = split;
+	}
+}
+
 static blk_qc_t dm_process_bio(struct mapped_device *md,
 			       struct dm_table *map, struct bio *bio)
 {
+	blk_qc_t ret = BLK_QC_T_NONE;
+	struct dm_target *ti = md->immutable_target;
+
+	if (unlikely(!map)) {
+		bio_io_error(bio);
+		return ret;
+	}
+
+	if (!ti) {
+		ti = dm_table_find_target(map, bio->bi_iter.bi_sector);
+		if (unlikely(!ti || !dm_target_is_valid(ti))) {
+			bio_io_error(bio);
+			return ret;
+		}
+	}
+
+	/*
+	 * If in ->make_request_fn we need to use blk_queue_split(), otherwise
+	 * queue_limits for abnormal requests (e.g. discard, writesame, etc)
+	 * won't be imposed.
+	 */
+	if (current->bio_list) {
+		blk_queue_split(md->queue, &bio);
+		if (!is_abnormal_io(bio))
+			dm_queue_split(md, ti, &bio);
+	}
+
 	if (dm_get_md_type(md) == DM_TYPE_NVME_BIO_BASED)
-		return __process_bio(md, map, bio);
+		return __process_bio(md, map, bio, ti);
 	else
 		return __split_and_process_bio(md, map, bio);
 }
diff --git a/drivers/md/persistent-data/dm-block-manager.c b/drivers/md/persistent-data/dm-block-manager.c
index 492a3f8ac1199b841215758119e4167b46d9b71e..3972232b80378fa855513ac9f3b088ff7049c35c 100644
--- a/drivers/md/persistent-data/dm-block-manager.c
+++ b/drivers/md/persistent-data/dm-block-manager.c
@@ -462,7 +462,7 @@ int dm_bm_read_lock(struct dm_block_manager *bm, dm_block_t b,
 	int r;
 
 	p = dm_bufio_read(bm->bufio, b, (struct dm_buffer **) result);
-	if (unlikely(IS_ERR(p)))
+	if (IS_ERR(p))
 		return PTR_ERR(p);
 
 	aux = dm_bufio_get_aux_data(to_buffer(*result));
@@ -498,7 +498,7 @@ int dm_bm_write_lock(struct dm_block_manager *bm,
 		return -EPERM;
 
 	p = dm_bufio_read(bm->bufio, b, (struct dm_buffer **) result);
-	if (unlikely(IS_ERR(p)))
+	if (IS_ERR(p))
 		return PTR_ERR(p);
 
 	aux = dm_bufio_get_aux_data(to_buffer(*result));
@@ -531,7 +531,7 @@ int dm_bm_read_try_lock(struct dm_block_manager *bm,
 	int r;
 
 	p = dm_bufio_get(bm->bufio, b, (struct dm_buffer **) result);
-	if (unlikely(IS_ERR(p)))
+	if (IS_ERR(p))
 		return PTR_ERR(p);
 	if (unlikely(!p))
 		return -EWOULDBLOCK;
@@ -567,7 +567,7 @@ int dm_bm_write_lock_zero(struct dm_block_manager *bm,
 		return -EPERM;
 
 	p = dm_bufio_new(bm->bufio, b, (struct dm_buffer **) result);
-	if (unlikely(IS_ERR(p)))
+	if (IS_ERR(p))
 		return PTR_ERR(p);
 
 	memset(p, 0, dm_bm_block_size(bm));
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index e528baebad6964124e6287a890cd12f81bffa561..b0672756d0562697238cb9cf53775c3c48d87a4a 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -10,6 +10,7 @@
 
 #include <linux/bio.h>
 #include <linux/blkdev.h>
+#include <linux/dm-ioctl.h>
 #include <linux/math64.h>
 #include <linux/ratelimit.h>
 
@@ -315,12 +316,6 @@ struct dm_target {
 	 * whether or not its underlying devices have support.
 	 */
 	bool discards_supported:1;
-
-	/*
-	 * Set if the target required discard bios to be split
-	 * on max_io_len boundary.
-	 */
-	bool split_discard_bios:1;
 };
 
 /* Each target can link one of these into the table */
@@ -431,6 +426,14 @@ void dm_remap_zone_report(struct dm_target *ti, sector_t start,
 			  struct blk_zone *zones, unsigned int *nr_zones);
 union map_info *dm_get_rq_mapinfo(struct request *rq);
 
+/*
+ * Device mapper functions to parse and create devices specified by the
+ * parameter "dm-mod.create="
+ */
+int __init dm_early_create(struct dm_ioctl *dmi,
+			   struct dm_target_spec **spec_array,
+			   char **target_params_array);
+
 struct queue_limits *dm_get_queue_limits(struct mapped_device *md);
 
 /*
@@ -609,7 +612,7 @@ do {									\
  */
 #define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
 
-static inline sector_t to_sector(unsigned long n)
+static inline sector_t to_sector(unsigned long long n)
 {
 	return (n >> SECTOR_SHIFT);
 }
diff --git a/include/uapi/linux/dm-ioctl.h b/include/uapi/linux/dm-ioctl.h
index d1e49514977bc03732922e37272c408c2665c8f3..f396a82dfd3e61bb1810f4cacf6fcb9b9eefa37b 100644
--- a/include/uapi/linux/dm-ioctl.h
+++ b/include/uapi/linux/dm-ioctl.h
@@ -270,9 +270,9 @@ enum {
 #define DM_DEV_SET_GEOMETRY	_IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)
 
 #define DM_VERSION_MAJOR	4
-#define DM_VERSION_MINOR	39
+#define DM_VERSION_MINOR	40
 #define DM_VERSION_PATCHLEVEL	0
-#define DM_VERSION_EXTRA	"-ioctl (2018-04-03)"
+#define DM_VERSION_EXTRA	"-ioctl (2019-01-18)"
 
 /* Status bits */
 #define DM_READONLY_FLAG	(1 << 0) /* In/Out */